Golang 嵌入接口

在Go语言中，接口是一个方法签名的集合，它也是一种类型，意味着你可以创建一个接口类型的变量。我们知道Go语言不支持继承，但Go语言的接口完全支持嵌入。在嵌入中，一个接口可以嵌入其他接口，或者一个接口可以将其他接口的方法签名嵌入其中，两者的结果都是一样的，如例1和例2所示。你可以在一个接口中嵌入任意数量的接口。当一个接口嵌入其他接口时，如果我们对这些接口的方法做了任何修改，那么它也会反映在嵌入的接口中，如例3所示。

语法

type interface_name1 interface {

    Method1()
}

type interface_name2 interface {

    Method2()
}

type finalinterface_name interface {

    interface_name1
    interface_name2
}

or

type interface_name1 interface {

    Method1()
}

type interface_name2 interface {

    Method2()
}

type finalinterface_name interface {

    Method1()
    Method2()
}

例1 :

// Go program to illustrate the concept
// of the embedding interfaces
package main
 
import "fmt"
 
// Interface 1
type AuthorDetails interface {
 
    details()
}
 
// Interface 2
type AuthorArticles interface {
 
    articles()
}
 
// Interface 3
 
// Interface 3 embedded with
// interface 1 and 2
type FinalDetails interface {
 
    AuthorDetails
    AuthorArticles
}
 
// Structure
type author struct {
 
    a_name    string
    branch    string
    college   string
    year      int
    salary    int
    particles int
    tarticles int
}
 
// Implementing method of
// the interface 1
func (a author) details() {
 
    fmt.Printf("Author Name: %s", a.a_name)
    fmt.Printf("\nBranch: %s and passing year: %d",
                                  a.branch, a.year)
    fmt.Printf("\nCollege Name: %s", a.college)
    fmt.Printf("\nSalary: %d", a.salary)
    fmt.Printf("\nPublished articles: %d", a.particles)
}
 
// Implementing method
// of the interface 2
func (a author) articles() {
 
    pendingarticles := a.tarticles - a.particles
    fmt.Printf("\nPending articles: %d", pendingarticles)
}
 
// Main value
func main() {
 
    // Assigning values
    // to the structure
    values := author{
        a_name:    "Mickey",
        branch:    "Computer science",
        college:   "XYZ",
        year:      2012,
        salary:    50000,
        particles: 209,
        tarticles: 309,
    }
 
    // Accessing the methods of
    // the interface 1 and 2
    // Using FinalDetails interface
    var f FinalDetails = values
    f.details()
    f.articles()
}

输出

Author Name: Mickey
Branch: Computer science and passing year: 2012
College Name: XYZ
Salary: 50000
Published articles: 209
Pending articles: 100

解释： 如上例所示，我们有三个接口。接口1和2是简单的接口，接口3是嵌入式接口，其中包含了1和2的接口。因此，如果界面1和界面2发生任何变化，都会反映在界面3上。而接口3可以访问接口1和2中的所有方法。

例2 :

// Go program to illustrate the
// concept of embedding interfaces
package main
 
import "fmt"
 
// Interface 1
type AuthorDetails interface {
    details()
}
 
// Interface 2
type AuthorArticles interface {
    articles()
}
 
// Interface 3
 
// Interface 3 embedded with
// interface 1 and 2's methods
type FinalDetails interface {
 
    details()
    articles()
}
 
// Structure
type author struct {
 
    a_name    string
    branch    string
    college   string
    year      int
    salary    int
    particles int
    tarticles int
}
 
// Implementing method of
// the interface 1
func (a author) details() {
 
    fmt.Printf("Author Name: %s", a.a_name)
    fmt.Printf("\nBranch: %s and passing year: %d", a.branch, a.year)
    fmt.Printf("\nCollege Name: %s", a.college)
    fmt.Printf("\nSalary: %d", a.salary)
    fmt.Printf("\nPublished articles: %d", a.particles)
}
 
// Implementing method
// of the interface 2
func (a author) articles() {
    pendingarticles := a.tarticles - a.particles
    fmt.Printf("\nPending articles: %d", pendingarticles)
}
 
// Main value
func main() {
 
    // Assigning values
    // to the structure
    values := author{
        a_name:    "Mickey",
        branch:    "Computer science",
        college:   "XYZ",
        year:      2012,
        salary:    50000,
        particles: 209,
        tarticles: 309,
    }
 
    // Accessing the methods
    // of the interface 1 and 2
    // Using FinalDetails interface
    var f FinalDetails = values
    f.details()
    f.articles()
}

输出

Author Name: Mickey
Branch: Computer science and passing year: 2012
College Name: XYZ
Salary: 50000
Published articles: 209
Pending articles: 100

解释： 如上例所示，我们有三个接口。接口1和2是简单的接口，接口3是内嵌的接口，其中包含了接口1和2的方法签名。因此，如果接口1和接口2的方法有任何变化，都不会反映在接口3中，直到我们在接口3中明确定义。而接口3只有在接口3中提到的情况下才可以访问接口1和2中的所有方法。

// Go program to illustrate the concept
// of the embedding interfaces
package main
 
import "fmt"
 
// Interface 1
type AuthorDetails interface {
    details()
}
 
// Interface 2
type AuthorArticles interface {
    articles()
    picked()
}
 
// Interface 3
// Interface 3 embedded with interface
// 1's method and interface 2
// And also contain its own method
type FinalDetails interface {
    details()
    AuthorArticles
    cdeatils()
}
 
// Structure
type author struct {
    a_name    string
    branch    string
    college   string
    year      int
    salary    int
    particles int
    tarticles int
    cid       int
    post      string
    pick      int
}
 
// Implementing method
// of the interface 1
func (a author) details() {
 
    fmt.Printf("Author Name: %s", a.a_name)
    fmt.Printf("\nBranch: %s and passing year: %d", a.branch, a.year)
    fmt.Printf("\nCollege Name: %s", a.college)
    fmt.Printf("\nSalary: %d", a.salary)
    fmt.Printf("\nPublished articles: %d", a.particles)
}
 
// Implementing methods
// of the interface 2
func (a author) articles() {
 
    pendingarticles := a.tarticles - a.particles
    fmt.Printf("\nPending articles: %d", pendingarticles)
}
 
func (a author) picked() {
 
    fmt.Printf("\nTotal number of picked articles: %d", a.pick)
}
 
// Implementing the method
// of the embedded interface
func (a author) cdeatils() {
 
    fmt.Printf("\nAuthor Id: %d", a.cid)
    fmt.Printf("\nPost: %s", a.post)
}
 
// Main value
func main() {
 
    // Assigning values to the structure
    values := author{
     
        a_name:    "Mickey",
        branch:    "Computer science",
        college:   "XYZ",
        year:      2012,
        salary:    50000,
        particles: 209,
        tarticles: 309,
        cid:       3087,
        post:      "Technical content writer",
        pick:      58,
    }
 
    // Accessing the methods
    // of the interface 1 and 2
    // Using FinalDetails interface
    var f FinalDetails = values
    f.details()
    f.articles()
    f.picked()
    f.cdeatils()
}

输出

Author Name: Mickey
Branch: Computer science and passing year: 2012
College Name: XYZ
Salary: 50000
Published articles: 209
Pending articles: 100
Total number of picked articles: 58
Author Id: 3087
Post: Technical content writer